A major objective for airlines and airport management is to increase the overall flight capacity, by limiting the number of missed and delayed flights, while maintaining a sufficient level of flight safety. Each delayed flight has a tremendous economic cost, as well as being a severe inconvenience for the passengers and flight crew. If for example a pilot experiences poor visibility when approaching the runway prior to landing, the aircraft landing may need to be delayed, or the flight rerouted to another destination. Likewise, if there is known to be poor visibility at the destination region, the aircraft take-off may be cancelled or delayed, disrupting the original flight schedule as well as impacting the scheduling of other planned flights. Poor visibility is generally the result of fog, but other inclement weather conditions, such as rain, snow, sleet, dust storms or smoke, can also restrict visibility in the surrounding environment. Moreover, besides causing flight delays, poor visibility for the pilot has serious safety implications and increases the likelihood of an accident occurring.
The large expansion of air travel in recent years and corresponding increase in the level of air traffic, a trend which appears to continue in the future, only intensifies the safety repercussions of poor visibility weather conditions. Recent developments in the aviation world has also seen the introduction of the very light jet (VLJ), a small jet aircraft flown by a single pilot and carrying only a handful of passengers. The VLJ is relatively inexpensive as compared to the larger commuter aircrafts, and is projected to capture a substantial portion of the market for air travel, which will serve to exacerbate air traffic and associated logistic problems. These smaller aircrafts are also associated with a greater likelihood of flight problems and accidents, as the pilots tend to be less trained and experienced, and are usually operating in less equipped airfields. Furthermore, the air traffic controllers and other flight control personnel are required to devote an extra amount of time dealing with such flights to ensure that everything proceeds safely. This prevents the air traffic controllers from handling other flights, thereby limiting the overall flight capacity, contributing to further escalation of the air traffic congestion at airports.
Several existing systems are designed to improve flight safety and enhance situational awareness by providing supplemental visual data to the pilot. The visual data may be projected onto a head-up display (HUD) or a head-down display. The data may include an enhanced image of the external environment in front of the aircraft, as well as relevant flight and navigational information. For example, an enhanced vision system (EVS) projects an image onto a HUD, such that the pilot sees the projected image overlayed in a conformal manner over the outside view. This enables the pilot to see features (such as runways, landing approach markers, other aircrafts, mountains, buildings, and other terrain), which otherwise could not be seen during night and low visibility conditions. The image may be obtained using an external imaging device, which detects light outside the visible range, such as a forward looking infrared (FLIR) camera. The image may also be obtained from a database containing predefined images of the surrounding environment. The image may further incorporate data link information.
Systems which display visual data in a two-dimensional (2D) format, such as head down displays, offer somewhat limited situational awareness, as it is difficult for the pilot to translate a 2D image representation into a real world three-dimensional (3D) comprehension. While providing limited situational awareness, head-down displays also increase the pilot workload, due to the diversion of the pilot line-of-sight and attention to a separate display. While head-up displays can deliver local real world situational awareness with a decreased workload, they generally provide only a limited field of view. Consequently, many areas which may contain important information for the pilot (or where important information should be displayed) are essentially blocked from view, thereby limiting the overall situational awareness.
Flight errors may occur due to miscommunication between the air traffic controller and the pilot. The air traffic controller may send instructions or flight information to the pilot, but the pilot may not fully understand or correctly interpret the received information. The air traffic controller utilizes a 2D image representation to generate the flight instructions, whereas the pilot must translate these instructions into the real world 3D environment. The need to translate the information into a verbal format inevitably introduces errors of precision or interpretation. Even when confirmation is performed, verbally or through other means, there is no guarantee that the instructions were correctly understood. The two sides may have different perspectives with respect to the same set of instructions.
PCT International Publication No. WO2007/006762 to Thales, entitled “Optoelectronic device for assisting aircraft taxiing comprising dedicated imaging”, is directed to a device for assisting aircraft taxiing on an airport traffic lane. A Head-Up collimator displays symbology superimposed on the out-the-window scene in the visual field of the pilot. A calculator dedicated to the collimator generates the symbology, which can be divided into 2D symbols and 3D symbols. The 3D symbols include the axial marks of the traffic lane and the lateral safety marks of the traffic lane, and are superimposed exactly on the external elements they represent. The axial marks are depicted as a series of rectangular forms arranged at regular intervals, representing the center line of the traffic lane. The lateral safety marks are depicted as plots at regular intervals, representing the external limit or boundary of the traffic lane. During bends in the traffic lane, the lateral safety marks are depicted as plots of variable height on the outside of the bend. The height of the plots increases gradually during the beginning of the bend, remains constant until the end of the bend, and then decreases gradually following the bend. The height of the plots is lower than the eye level of the pilot above the traffic lane, such that all the plots appear under a depicted horizon line. The 2D symbols include symbols representing a change of direction, the location of the main undercarriage, and an aerial view of the aircraft location on the bend. The set of symbols representing a change of direction include: a curved arrow, indicating the bend direction and curve angle; the name of the following traffic lane; and a text indication of the bend along with the remaining distance to complete the bend. The set of symbols representing the location of the main undercarriage include: a model of the aircraft undercarriage that encompasses the bogies; a representation of the traffic lane on the same scale as the undercarriage model; and markings representing the ideal location of the external edges of the bogies when the aircraft is centered on the traffic lane. The set of symbols representing the aerial view of the aircraft location on the bend, main undercarriage include: rectangle-shaped marks arranged at regular intervals representing the center line of the traffic lane; lateral safety marks of the traffic line; an undercarriage model representing an aerial view of the undercarriage and the front wheel; and an aircraft model representing an aerial view of the aircraft.
U.S. Pat. No. 6,119,055 to Richman, entitled “Real time imaging system and method for use in aiding a landing operation of an aircraft in obscured weather conditions”, is directed to an apparatus and method for aiding an operator of an aircraft in visualizing a runway during inclement weather conditions. The apparatus includes a plurality of LED assemblies disposed on opposite sides of the runway; a radio frequency (RF) transmitter disposed on a tower near the end of the runway; and an imaging system mounted on the aircraft. Each of the LED assemblies includes a plurality of LEDs, a current driver circuit and an RF receiver. The imaging system includes an RF receiver, a processor, a camera and a display. The RF transmitter transmits RF signals toward the LED assemblies, causing the RF receiver to signal the driver circuit to energize the LEDs intermittently, in synchronization with the carrier frequency of the RF signal. As the aircraft approaches the runway, the imaging system receives the RF signals transmitted by the RF transmitter. The RF receiver of the imaging system signals the processor, which controls the operation of the camera (e.g., a CCD) in synchronization with the RF signal, such that the time and duration the camera is turned on matches the time and duration the LED is energized, at twice the frequency. In particular, the first frame captured by the camera occurs when the LEDs are turned on, the second frame captured occurs when the LEDs are turned off, the third frame occurs when the LEDs are turned on, the fourth frame occurs when the LEDs are turned off, and so forth. The frames captured when the LEDs are turned on, include radiant energy from the LEDs together with radiant background energy resulting from other light sources. The frames captured when the LEDs are turned off include only the radiant background energy. The processor (e.g., a frame grabber) receives all the frames captured by the camera, and subtracts (pixel by pixel) the digital information of each frame taken when the LEDs are turned off, from the digital information of the previous frame. The display (e.g., a HUD) presents the resultant filtered image, which includes only the light generated by the LEDs. The displayed image provides the pilot with an ability to discern the runway at a further distance away during inclement weather conditions, also known as an increased runway visible range (RVR).
U.S. Pat. No. 6,232,602 to Kerr entitled “Enhanced vision system sensitive to infrared radiation”, is directed to an enhanced vision system (EVS) for generating a graphical representation of a surrounding background scene to assist piloting an aircraft. The system includes a computer, a display (e.g., a HUD), an electric light source imager, and an ambient background scene imager. The electric light source imager detects short wavelength infrared radiation (SWIR), in the range of 1.5-1.7 μm, to obtain an image of electric navigation lights. The electric light source assembly may include a spectral filter, to optimize sensitivity and adapt to non-daylight operation. The center of each radiation source is identified (by determining the peaks or local maxima), and a video signal is generated where each peak is represented by a dot of predefined size. The ambient background scene imager detects long wavelength infrared radiation (LWIR), e.g. 8-14 μm, or alternatively medium wavelength infrared radiation (MWIR), e.g. 3-5 μm, to obtain an image of the surrounding background, such as runway edges and markings, terrain, structures and vehicles. The computer combines the video signals generated by the electric light source imager and the ambient background scene imager. The fused image is then displayed, in alignment with the pilot perspective of the real world perceived through the aircraft windshield. The system may also incorporate a visible light imager, which detects light in the range of 0.4-0.7 μm. The images may also be supplemented with a predefined database of patterns and features, along with their global location. A computer generated image based on object recognition of the patterns is fitted to the image from the sensors to add missing details, such as if atmospheric conditions prevent the sensors from sensing all the navigation lights.
U.S. Pat. No. 6,862,501 to He, entitled “Method for producing 3D perspective view avionics terrain displays”, is directed to an aircraft display system and method, which displays terrain features in 3D. A plurality of sensors is arranged at predetermined intervals along a road. The system includes a graphics processor, a display element, and a plurality of data sources (e.g., a terrain database, a weather radar data source, a terrain avoidance and warning system, a navigational database, and a traffic and collision avoidance system). The processor receives inertial information (i.e., position, speed, direction), and obtains terrain data and navigational data from the databases based on the inertial information. The processor renders an image of the terrain, the navigational data, and flight path, which is displayed on the display element. The terrain is displayed with reduced detail in certain areas, in order to reduce the computational load of the processor. In particular, the terrain is initially depicted as a square patch of N×N terrain elevation data points, with each data point color-coded based on the absolute terrain elevation. The data points are connected with polygons, such as triangles, such that they appear continuous on a graphic display, thereby forming a polygon mesh. An error bound array is constructed for a triangle binary tree based square patch. The look forward viewing volume is determined based on the current location, heading, and desired viewing angle. The triangle binary tree based polygon mesh is computed, where the areas within the viewing volume use smaller error bounds, so that the triangle binary tree descends to lower levels to show more detail. The terrain color texture map is loaded onto the terrain polygon mesh and displayed. The current location and heading are updated, and the process is repeated.
U.S. Pat. No. 7,091,881 to Judge et al, entitled “Integrated hover display with augmented approach to hover symbology cueing for degraded visual environmental conditions”, is directed to an integrated display system for a rotary wing aircraft to facilitate approach, hover and landing in degraded visual environmental (DVE) conditions. A sensor system having a variety of sensors (e.g., a radar altimeter, an air data system, a digital map, terrain database, global positioning system) collects information from the environment. An imaging system (e.g., a FLIR camera, a video camera) acquires imagery information. A mission computer determines flight information (e.g., velocity, height above ground, ground speed, wind direction, wind speed, location of landing zone, location of other aircrafts) based on data from the sensor system. A data fusion processor combines data received from the sensor system and the mission computer. For example, the data fusion processor may generate a synthetic image, by fusing information from a sensor and an imager, to represent terrain that may not be visible under DVE conditions. The primary flight display of the aircraft includes a hover display, which displays combined symbology received from the data fusion processor, in a single integrated data set. The hover display may be implemented as a helmet mounted display and a heads up display, where the helmet mounted display provides the pilot with visual information overlayed on the outside scene and stabilized using a head-tracking device. The symbology displayed by the hover display may include, for example, aircraft location relative to the desired landing point, aircraft velocity, acceleration, altitude, rate of descent, the presence and location of terrain obstacles, as well as indications of heading drift and lateral drift. The symbology also provides predictive information, such as the altitude at a future point, by means of an altitude ascent/descent tape. Certain symbols may be color coded, to indicate where the associated quantity lies with respect to acceptable limits.